编译时和运行时之间的差异就是精明的理论家所说的阶段差异的一个例子。它是最难学习的概念之一，特别是对于没有太多编程语言背景的人来说。要解决这个问题，我发现问一下很有帮助

程序满足哪些不变量? 在这个阶段会出现什么问题? 如果阶段成功，后置条件是什么(我们知道什么)? 输入和输出是什么(如果有的话)?

编译时

The program need not satisfy any invariants. In fact, it needn't be a well-formed program at all. You could feed this HTML to the compiler and watch it barf... What can go wrong at compile time: Syntax errors Typechecking errors (Rarely) compiler crashes If the compiler succeeds, what do we know? The program was well formed---a meaningful program in whatever language. It's possible to start running the program. (The program might fail immediately, but at least we can try.) What are the inputs and outputs? Input was the program being compiled, plus any header files, interfaces, libraries, or other voodoo that it needed to import in order to get compiled. Output is hopefully assembly code or relocatable object code or even an executable program. Or if something goes wrong, output is a bunch of error messages.

运行时

We know nothing about the program's invariants---they are whatever the programmer put in. Run-time invariants are rarely enforced by the compiler alone; it needs help from the programmer. What can go wrong are run-time errors: Division by zero Dereferencing a null pointer Running out of memory Also there can be errors that are detected by the program itself: Trying to open a file that isn't there Trying find a web page and discovering that an alleged URL is not well formed If run-time succeeds, the program finishes (or keeps going) without crashing. Inputs and outputs are entirely up to the programmer. Files, windows on the screen, network packets, jobs sent to the printer, you name it. If the program launches missiles, that's an output, and it happens only at run time :-)

对于S.O.来说，这不是一个好问题(这不是一个特定的编程问题)，但总的来说，这不是一个坏问题。

如果您认为这是微不足道的:那么读时与编译时的区别是什么呢?什么时候这是一个有用的区别?编译器在运行时可用的语言呢?Guy Steele(不是笨蛋，他)在CLTL2中写了7页关于EVAL-WHEN的内容，CL程序员可以使用它来控制这一点。两句话只能勉强给出一个定义，而定义本身还远远不够解释。

In general, it's a tough problem that language designers have seemed to try to avoid. They often just say "here's a compiler, it does compile-time things; everything after that is run-time, have fun". C is designed to be simple to implement, not the most flexible environment for computation. When you don't have the compiler available at runtime, or the ability to easily control when an expression is evaluated, you tend to end up with hacks in the language to fake common uses of macros, or users come up with Design Patterns to simulate having more powerful constructs. A simple-to-implement language can definitely be a worthwhile goal, but that doesn't mean it's the end-all-be-all of programming language design. (I don't use EVAL-WHEN much, but I can't imagine life without it.)

关于编译时和运行时的问题空间是巨大的，而且在很大程度上仍未被探索。这并不是说S.O.是进行讨论的正确场所，但我鼓励人们进一步探索这一领域，特别是那些对它应该是什么没有先入为主概念的人。这个问题既不简单也不愚蠢，我们至少可以给检察官指出正确的方向。

不幸的是，我不知道任何好的参考资料。CLTL2稍微讲了一下，但对于学习它并不是很好。

编译时间:您作为开发人员编译代码的时间段。

运行时间:用户运行你的软件的时间段。

你需要更明确的定义吗?

编制时间:

在编译时执行的操作在最终程序运行时几乎不会产生任何开销，但在构建程序时可能会产生很大开销。

运行时:

或多或少完全相反。构建时成本小，运行程序时成本大。

从另一边;如果在编译时执行了某些操作，那么它只在您的机器上运行;如果在运行时执行了某些操作，那么它将在用户的机器上运行。

相关性

An example of where this is important would be a unit carrying type. A compile time version (like Boost.Units or my version in D) ends up being just as fast as solving the problem with native floating point code while a run-time version ends up having to pack around information about the units that a value are in and perform checks in them along side every operation. On the other hand, the compile time versions requiter that the units of the values be known at compile time and can't deal with the case where they come from run-time input.

您可以通过阅读实际代码来理解代码编译结构。运行时结构并不清楚，除非您了解所使用的模式。

例如:在强类型语言中，类型可以在编译时或运行时检查。在编译时，这意味着如果类型不兼容，编译器将报错。在运行时，意味着你可以很好地编译你的程序，但在运行时，它会抛出一个异常。